Where Is The Spark Plug On A Lawn Mower?

The satisfying hum of a lawnmower, the crisp scent of freshly cut grass – these are the hallmarks of a well-maintained lawn. But what happens when that familiar sound turns into a sputtering cough? The culprit could be a faulty spark plug, a crucial component that ignites the fuel-air mixture in your mower’s engine. But where exactly is this little piece of magic hidden? This article will guide you through the process of locating your lawnmower’s spark plug, explaining the essential tools and safety precautions you need to know.

A Quick Overview

The spark plug sits on the top of the engine cylinder, usually covered by a wire boot and a small metal cap. You’ll often find it tucked away near the air filter or the carburetor. While the exact location can vary depending on your mower model, understanding the general layout and recognizing key components will make the search much easier.

Identifying Your Lawn Mower’s Engine Type

Before we embark on the spark plug hunt, it’s crucial to identify your lawnmower’s engine type. Knowing this will provide valuable clues as to where to look. The two most common types are:

1. Small Engines with Overhead Valves (OHV)

These are typically found on newer lawnmowers and are characterized by a valve cover on the top of the engine. The spark plug is usually located under this valve cover, secured by one or two bolts.

2. Small Engines with Side Valves (SV)

These are more common in older mowers and have a side-mounted valve cover. The spark plug is typically situated on the side of the engine, often near the exhaust manifold.

Locating The Spark Plug: A Step-by-Step Guide

Now, armed with knowledge of your engine type, let’s dive into the hunt for that elusive spark plug.

1. Prepare Your Work Area

Before getting your hands dirty, it’s essential to prepare a safe workspace. Find a clean, level surface and ensure you have adequate lighting. Also, disconnect the spark plug wire from the spark plug to prevent accidental ignition.

2. Identify The Spark Plug Wire

The spark plug wire is usually a thick, rubber-coated cable that connects to the spark plug. It’s often easily identifiable due to its contrasting color against the engine’s metallic surface.

3. Follow The Spark Plug Wire

The spark plug wire acts as your compass to the spark plug itself. Carefully follow the wire, tracing its path from its connection point. You’ll usually find the spark plug wire routed to a metal cap or boot that sits atop the spark plug.

4. Remove The Spark Plug Wire Boot (If Applicable)

If a boot covers the spark plug, gently pull it off. You can usually achieve this with a gentle tug, ensuring you avoid pulling on the wire itself.

5. Identify The Spark Plug

The spark plug is a small, cylindrical component with a central electrode and a terminal nut. The terminal nut is where the spark plug wire attaches.

6. Troubleshooting Tips:

  • Don’t Panic: If the spark plug is elusive, don’t get discouraged! Refer to your lawnmower’s manual for specific instructions and diagrams that can provide additional guidance.
  • Consult Your Owner’s Manual: Your owner’s manual should have a detailed diagram outlining the exact location of the spark plug for your specific mower model.
  • Search Online: If you’ve lost your owner’s manual, a quick online search for your mower model can reveal diagrams and resources that can help pinpoint the spark plug’s location.

Safety Precautions: Keeping Your Spark Plug Adventure Secure

Remember that working with a lawnmower engine comes with inherent risks. Here are some essential safety precautions to keep in mind:

  • Disconnect The Battery: Always disconnect the battery terminal before working on your lawnmower’s engine. This will prevent accidental electrical shock.
  • Wear Eye Protection: Goggles or safety glasses can protect your eyes from flying debris or potential splashes.
  • Use Gloves: Gloves will provide a secure grip and protect your hands from grime and potential cuts.
  • Keep Away From Flammables: Work in a well-ventilated area and keep flammable materials away from the engine.
  • Never Start The Engine With The Spark Plug Removed: Running the engine without a spark plug can damage the engine.

Replacing Your Spark Plug: A Quick Guide

Once you’ve successfully located the spark plug, you might need to replace it. Here’s a simple guide to make the process smooth:

1. Use The Correct Spark Plug:

Refer to your owner’s manual for the correct spark plug type and specifications for your lawnmower. Using the wrong spark plug can lead to engine problems.

2. Gently Unscrew The Spark Plug:

Use a spark plug wrench to gently unscrew the spark plug, turning it counterclockwise.

3. Install The New Spark Plug:

Screw in the new spark plug by hand until it’s snug. Then, use the spark plug wrench to tighten it further, but avoid overtightening.

4. Reconnect The Spark Plug Wire:

Connect the spark plug wire to the new spark plug’s terminal nut, ensuring a secure connection.

Final Thoughts

Locating your lawnmower’s spark plug doesn’t have to be a daunting task. By understanding the basics of engine types, following the steps outlined above, and prioritizing safety, you can successfully navigate this process. Remember, a properly functioning spark plug is essential for a smooth-running lawnmower, allowing you to enjoy those satisfying moments of freshly cut grass without any unnecessary hiccups.


Q1: Why do I need to know where the spark plug is?

Knowing where the spark plug is on your lawn mower is essential for several reasons. Firstly, it allows you to easily access and check the spark plug’s condition. A worn-out or fouled spark plug can cause your mower to start poorly or not at all. Secondly, you’ll need to remove the spark plug before performing any maintenance that involves working on the engine, such as cleaning the carburetor or changing the oil. Lastly, it’s important to know where the spark plug is located in case of an emergency, as you may need to disconnect it to prevent accidental starting.

Q2: Where is the spark plug typically located on a lawn mower?

The spark plug is usually located on the top of the engine, near the cylinder head. You’ll often find it under a spark plug cover, a small metal cap that protects the plug from dirt and debris. Look for a wire leading from the spark plug cover to the ignition system. The wire will connect to a metal cap that attaches to the top of the spark plug.

Q3: How do I find the spark plug on my lawn mower?

To locate the spark plug on your lawn mower, start by looking for the engine’s cylinder head. This is typically the topmost part of the engine, and it’s usually made of metal. Once you find the cylinder head, look for a small metal cap with a wire attached to it. This cap covers the spark plug. If you can’t find the spark plug cover, you can try searching for a metal rod with a small gap on its side, which is the spark plug.

Q4: What does the spark plug look like?

A spark plug is a small, cylindrical component with a threaded end and a metal cap on the other end. It typically has a central electrode that protrudes from the metal cap and a side electrode that is embedded in the ceramic insulator. The central electrode is connected to the ignition wire, while the side electrode is connected to the engine’s ground.

Q5: What should I do if I can’t find the spark plug?

If you can’t find the spark plug on your lawn mower, consult your owner’s manual for specific instructions. The manual will typically include a diagram showing the location of the spark plug and other engine components. If you don’t have the manual, you can try searching online for a diagram specific to your lawn mower model. Alternatively, you can contact the lawn mower manufacturer for assistance.

Q6: How often should I check or replace my spark plug?

It’s recommended to check the condition of your lawn mower spark plug every 50 hours of use or annually, whichever comes first. If you notice any signs of wear or damage, such as a worn-down electrode or a cracked insulator, you should replace the spark plug. A worn-out spark plug can lead to poor engine performance, difficulty starting, and increased fuel consumption.

Q7: Is it dangerous to work with the spark plug?

Working with the spark plug can be dangerous if proper safety precautions are not taken. Always disconnect the spark plug wire from the spark plug before removing the plug. This will prevent the engine from accidentally starting while you are working on it. Also, be careful not to drop the spark plug, as this can damage the threads and make it difficult to reinstall.

Leave a Comment